Type-bar antifriction-bearing.



A. T. BROWN.

TYPE BAR ANTIFRICTION BEARING.

APPLICATION FILED FELT-1', 1912. 1,159,645. Patented Nov. 9, 191-3.

1 INVEN ATTORNEYS WITNESSES:

TYPE-BAR ANTIFRICTEON-BEARING.

Specification of Letters Patent.

Patented Nov. 9, 1915.

Application filed February 14, 1912. Serial No. 677,578.

To aZl who: it may concern Be it known that I, i inexaicoau T. BROWN, ofSyracuse, in the county of Onondaga and State of Few York, have inventeda new and useful TypeBar Antifriction-Bearing, of which the following isa specification.

My invention relates to a blank for forming a thin ring-shaped type barbearing member provided with a peripheral thread at one edge and ahardened conical, or boyeled, ball race surface at its other edge, and

in which the axis of the thread will be coincioent with the axis of thecone, of which said ace surface is a peripheral section or zone.

In describing this invention, reference is had to the accompanyingdrawing, in which like characters designate corresponding parts in allthe views.

Figure 1 is a side elevation o type bar and a bearing embodying myinvention. Fig. 2 is a sectional view, partly in elevation, on line fifl i, Fig. 1. Fig. 3 is aft-agmentary view, partly in section, of acylindrical bar from which members of my hearing are formed. Fig. sis across-sectional view through the bar, shown'in Fig. 3. Fig. 5 is asectional view of a partially "completed bearing member, tools foroperation thereupon being shown in dotted lines. Fig. 6 is a sectionalView of the completed bearing member, additional tools being illustratedin dotted lines and diagrammatically. Fig. 7 is an enlarged view of thecomplete bearing member.

The invention is illustrated in connection with the type bar andsupporting segment employed in th well-hnown Smith-Pren'iier typcwritingmachine. The type bar is provided at one end with a type block and atits other end with an efve inclosing a set of antifriction balls heldbetween a ball race formed in the supporting segment, and acorresponding race formed by compleinental hearing mci'nbers adjustablysupported within the eye.

As is well-known to those skilled-in the art, it is necessary that thetype bar shall be of minimum width in the direction of the axis on whichit turns so that the number of bars required in a typewriting machinecan be accommodated in the limited )HCG arailable which. in a visible t)ewritin machine wherein the bars are not superimposed, 1S considerableless than an arc of 190. Consequently, the bearing mean aforesaid, whichare in the form of rings located within the eye of the type bar, must bevery thin in relation to their diameter. Each ring provided with asurface at one edge constituting one wall of a ball race, which must heof maximum hardness for resisting wea and at its other edge with athread for engaging" a complemental thread in the wall of the eye, or; afixed support for the rin so that the ring may be moved in an axialdirection for properly adjusting the bearing.

In order that a ball race, formed by a pair of ringbearing: members, maybe of uniform size 'tlirou hout, so as to prevent undue cramping or theballs at certain points in the race as the bar oscillated, it isabsolutely essential that the axes of the spirals of the threads in therings shall be coincident with the axes of the cones of which thehardened bearing surfaces of the rings constitute sections. In themanufacture of these bearing members, it is necessary to cut the threadsin the blank prior to subjecting the same to the hardening process forproperly hardening the surface which is to constitute the wall of a ballrace, and, owing to the thinness of the blank, this hardening treatmentfrequently results in the distortion thereof with a consequent twistingof the threaded edge in reference to the bearing surface, or adisplacement of the axis of the spiral of the threads in ref ercnce tothat of the cone, a section of which forms the bearing surface foresaid.My invention seeks to entirely eliminate this serious fault.

By my invention bearing members are composed of inner and, outer metalportions united together and of different character so that when one ofsaid members, in the course of its manufacture, is submitted to one ofthe well-known hardening processes, one of the portions of the memberhardens, and the other remains soft or relatively soft, and the bearingsurface of said member Which engages the antifriction members, is formedupon the hardened portion thereof, and the miuzhined surface, as theperipheral threads,

for supporting or securing the bearing member in the eye of the typebar, or con necting' the same to a suitable support, is formed on thesofter portion of the bearing member concentric with the hardenedbearing surface and after the formation of said hardened bearingsurface.

The inner and outer portions of the bearnan! ing member may be formed oftwo different said other portion may be composed of a" relatively softsteel which will not harden to the same extent as the steel to beprovided with a surface to engage the antifric-- tion members.Preferably, the inner .portion of the bearing member is hardened andprovided with a bearing surface for engaging the antif'riction members,and the outer portion is soft, or relatively soft, and is provided witha machined surface, as a threaded surface, for engaging a suitablesupport, as the eye of a type bar, but obviously the outer portionmay-be formed of the hardening metal, and the inner portion of the soft,or relatively soft, metal, in which event, the surface for engaging theantifriction members will be provided on the outer portion of thebearing member,

and the securing surface will be provided on the soft inner portion ofsaid bearing member.

A hearing member, constructed as described, is not only readily machinedto form the securing surface therefor after the hardening of the portionof the bearing member which resists the wear of the antifrictionmembers, but such a bearing member is liable to only a minimum amount ofdistortion since the softer metal holds the hardening metal in place toa greater or less extent, and further, such a member is absolutely truewhen in use, since the retaining surface is formed after the bearingsurface and true relatively thereto.

1 and 2 designate respectively the inner and outer portions of a bearingmember embodying my invention; and 3 and 4 desig-.

nate respectively the finished bearing surface provided on the innerhardened portion 1, and the finished securing or threaded surfaceprovided on the outer soft portion 2.

5 is the threaded eye of a type bar coacting with the threadedperipheries of the bearing members; and 6 are the antifriction members,or balls, engaging the surfaces 3 which form a raceway for said balls,and

also engaging a suitable support 7. The eye 5 is preferably splittransversely and provided with projecting ears and a screw 8 passedthrough said ears for clamping the bearing members in their adjustedposition in the eye 5.

The blanks constituting the subject-matter of this application arepreferably formed by suitable tools, such as those of a turret lathe,from a bar or other piece having an internal core 9 of steel suitablefor hardening, and an external shell or Wrapper 10 of material resistinghardening, or material hardening to a less extent than the core 9.

i In Fig. 3, I have shown a portion of such a bar and the internalcavity formed therein by one or more of the machine tools operating toproduce the blank from which my bearing member is formed, a line 11indicating the plane in which a cutoff tool operates to sever thepartially finished bearing member from the bar. ,The partially formedblank, cut, as described, from a bar such as illustrated in Fig. 3, ishardened by any well known process, such as the case-hardening method,or by heating the same and cooling in water, oil or other fluid. In thehardening process, the inner portion of the blank becomes hard, and theouter portion thereof remains soft, or relatively soft, and aspreviously stated, the outer soft, or relatively soft portion,'tends tominimize the amount of distortion of the bearing member due to itssubjection to the hardening process. The bearing surface 3 is thenformed upon the blank by suitable tools, such as a chuck 12 and arotating grinding tool 13, as shown in Fig. 5. The end face of thebearing member meeting the larger end of the surface 3 is trued or facedby a grinding tool 14, preferably, while said member is held by thechuck 12. After the formation of the surface 3, suitable tools operateto form the surface 4 concentric with said'surface 3, such toolscoacting with the surface 3 and the trued end face of the bearing memberto support the blank on said surface 3 in order that the surface i maybe absolutely concentric with the surface 3 or the axis of the spiral ofthe thread coincident with the axis of the cone of which the surface 3is a section.

In Fig. 6, I have indicated by dotted lines, a spring centering mandrel15 having a conical face 16 for engaging the face 3, and opposingmembers 17 and 18 for clamping the bearing member andholding the sameupon the mandrel 15, and I ha e shown .diagrammatically a threading orchasing tool 19 for forming the threaded surface 4.

To those skilled in the art, it will be readily apparent that bearingmembers constructed from blanks embodying my invention, are particularlyaccurate and efficient in operation.

l/Vhat I claim, is

1. A blank for forming a thinringshaped bearing member of a type bar,said blank having the wall of a ball race at one edge thereof and asurface to receive a thread in its other edge, said blank being formedin two sections, the one having the ball race being, hardened to agreater degree than the other, substantially as and for the purposedescribed. 7 Y

2. A blank for forming a thin ringshaped bearing member of a type bar,said blank comprising an inner section provided at its inner edge with aball race wall constituting the section of a cone, and an outer sectionunited to the periphery of the inner section, and of a material whichhardens to a lesser degree than the inner sections when the blank issubjected to a hardening process, said outer section having a peripheryfor receiving a screw thread, suhstantiall; as and for the purposespecified.

In testimony whereof, I have hereunto signed my name in the presence oftwo attesting witnesses, Syracuse, in the count of Onondaga, in theState of New Yorl this 26th day of January 1912.

ALEXANDER T. BROWN.

Witnesses C. E. Tonnnzson, Ixnz A. STILWELL.

